Bonding Flashcards
Define an ion and how they are formed?
An atom or molecule with a net charge
Formed via gain or loss of electrons
Oxidation or reduction
What charge are cations and anions?
Cations are positive
Anions are negative
How does a molecular ion form?
When groups of 2 or more atoms are covalently bonded and they gain or lose an electron.
The charge is shared across the entire molecule.
Give some examples of molecular ions.
NH4^+
OH^-
NO3^-
CO3^2-
SO4^2-
What are ionic compounds?
Compounds composed of oppositely charged ions.
Overall charge is neutral as the ions cancel out.
What is an ionic bond?
An electrostatic force of attraction between two oppositely charged ions
How are ionic bonds formed?
Generally between metals and non metals
Elements seek to gain a full outer shell and therefore will donate electrons to enable both atoms to have a full electron arrangement.
What are the structures of ionic compounds?
Exist as giant ionic lattices where each ion is surrounded by oppositely charged ions (3D lattice)
Give some properties of ionic substances.
High melting and boiling points- due to strong electrostatic forces of attraction and therefore lots of energy is required to break them.
Ionic substances are soluble in polar solvents- polar bonds are unequally shared and therefore have slight charges meaning that the lattice can be disrupted.
Conduct electricity- but only when dissolved or molten as the ions are free to move.
What is a covalent bond?
Strong electrostatic attraction between a shared pair of electrons and the nucleus of the bonded atoms.
Usually occurs between two non metals
Cl-Cl
Can have single double or triple covalent bonds
(C-C. O=O. N triple bonded to N
What is a dative covalent bond? (Coordinate bond)
Where one atom donates both the electrons in a covalent bond.
What types of structures do covalent bonds produce?
Simple covalent molecules:(molecular)
Made up of small simple molecules existing as a lattice in solid state. Each of the atoms are tightly held together by covalent bonds.
Giant covalent molecules:(macromolecular)
Atoms are joined to adjacent atoms by strong covalent bonds forming a network (giant lattice)
-eg diamond/graphite/ silicon dioxide
What are the properties of simple covalent molecules?
Low melting and boiling points due to weak intermolecular forces of attractions between the molecules so a small amount of energy is required in order to disrupt the forces.
Soluble in non polar solvents (like dissolves like)
Non conductors as they have no feee charged particles
What are the properties of giant covalent molecules?
High melting and boiling points due to strong covalent bonds requiring lots of energy to break the bonds between the atoms.
Insoluble in both polar and non polar solvents as the covalent bonds are not disrupted by either solvent.
Non conductors except graphite as between the layers of the lattice are delocalised electrons which are able to move and therefore when a voltage I applied it can carry a charge.
What are the main intermolecular forces?
Hydrogen bonds,
Van der waals
Dipole- dipole Forces